In recent years, fuel cell systems have been developed which have as an energy source a fuel cell that generates electric power through an electrochemical reaction between fuel gas and oxidant gas. This type of fuel cell system may be configured to return the fuel-off gas discharged from the fuel cell back to a fuel gas supply path for supplying fuel gas to the fuel cell, through a fuel-off gas circulation path, so that the fuel gas components contained in the fuel-off gas can effectively be utilized, the fuel-off gas circulation path being provided with a fuel-off gas circulation pump that takes in and discharges the fuel-off gas.
Meanwhile, the electrochemical reaction produces water on the cathode-side of the fuel cell, and the produced water flows through the electrolyte membrane toward the anode-side, resulting in the fuel-off gas containing water. Accordingly, a compressor is used as the above-described fuel-off gas circulation pump. The above compressor is configured to have an electric motor and a compression mechanism provided adjacently to the electric motor and driven by the electric motor, and in view of workability, etc., the compressor is fixed to an object to which the compressor is to be attached via a fixation part provided in the motor housing for the electric motor (see, for example, Patent Document 1).
Patent Document 1: Japanese laid-open patent publication No. 2004-162671